The long term objective of the research is to continue developing an animal model using the Fischer-344 laboratory rat for the study of the effects of age on the sense of taste. Special attention will be given to behavioral studies of the taste of sucrose. Since it has been shown that the palate of the rat, more so than the tongue, is of particular importance in mediating the taste of sucrose, the distribution and density of palatal taste buds will be studied in the Fischer-344 rat. The unique aspect of this description of palatal tastes buds will be that it will be made from rats with a known history of sucrose preference and sucrose thresholds, yielding a correlation between sucrose avidity and thresholds and density or distribution of palatal taste buds. Since the palatal taste buds are supported by the greater superficial petrosal nerve, a series of experiments will be conducted investigating the role of this nerve in the perception of sucrose by the rat. Finally, it will be observed if long term experience with sucrose in younger rats effects the avidity or thresholds for sucrose in older age. Emphasis will be placed on longitudinal rather than cross-sectioanl studies. The effects of age on taste in humans is not understood and the literature is filled with controversies in both psychophysical and anatomical studies. There is little literature on the changes in the palate with age. This may be very important especially for denture wearers. Variability is so large within age groups that without longitudinal studies changes occuring with age are obscured.